ImageView in android XML layout with layout_height="wrap_content" has padding top & bottom
I had a simular issue and resolved it using android:adjustViewBounds="true" on the ImageView.
<ImageView android:layout_width="fill_parent" android:layout_height="wrap_content" android:adjustViewBounds="true" android:contentDescription="@string/banner_alt" android:src="@drawable/banner_portrait" />